MOHAWK NATION OF AKWESASNE — The NYPD has gone on the reservation — sending its drug czar upstate to try to help cut off a massive pipeline of pot and ecstasy to the city run by Mohawk Indian smugglers on the Canadian border.

“I was astounded at how lenient the border is,” said Chief Joseph Resnick, head of the NYPD’s narcotics division.

He spoke after a trip six weeks ago to the Akwesasne reservation, which straddles the US-Canadian border and which he said supplies most of the high-potency marijuana and ecstasy sold on city streets.

“Once you cross into the US, you’re on the Indian reservation, which is sovereign land. The whole border is the real point of origin. When we bust large numbers of ecstasy and hydroponic pot, most of it comes through there.”

The feds say that in the last 10 years, more than $1 billion worth of marijuana has come through the reservation, which stretches five miles along the banks of the St. Lawrence River.

Smugglers traverse the fast-moving water in Jet Skis and high-powered speedboats. When the river freezes, they switch to snowmobiles.

The contraband is then packed into vans or trucks and driven down the New York State Thruway, authorities said.

The crossing, featured in last year’s Oscar-nominated movie “Frozen River,” is also a major route for illegal immigrants as well as huge quantities of untaxed liquor and cigarettes, investigators said.

The banks of the St. Lawrence are dotted with small docks and access roads. The 40-square-mile reservation includes territorial waters and about 100 islands. Interdiction efforts are often stymied by this geography — and influenced by politics.

While federal and state cops and Royal Canadian Mounted Police are allowed onto the reservation, they tread carefully. Some tribe members are openly hostile to them; a road sign labeled officers “terrorists.” The Mohawks have their own force on the “res,” as they call the Akwesasne reservation, and prefer to do their own policing.

Many of the traffickers are enterprising Mohawk tribe members in their 20s, attracted by fast money and better pay than they can make doing almost anything else.

One self-professed smuggler interviewed by The Post described how easy it was to elude US Border Patrol officers, who oversee the waterways on the US side of the river, and the Mounties’ marine patrol on the Canadian side.

“We go at night and run all night. I get on my Jet Ski, put on a helmet and night-vision goggles and just go. The boats we have are way faster than theirs. They can’t catch us.”

He said he earned about $300,000 in a two-week period last year after delivering a haul of cigarettes online, liquor and pot — and returned with large equipment bags stuffed with stacks of $100 bills, which took all night to count, he said.

“There are about 100 millionaires on the res,” he said. “A lot of them use the money to build these big houses or fix up their houses, then they put in safes to keep the cash.”

He said he knew of one man who had made $9 million smuggling drugs and contraband. Just about everyone on the reservation — home to 21,000 Mohawks divided into the St. Regis and Akwesasne tribes — knows someone in the smuggling trade.

A trip to Cornwall Island on the Canadian side revealed a disparity in wealth among residents. Some homes were dilapidated structures with rusted vehicles sitting on overgrown lawns. Others wouldn’t look out of place in the Hamptons. Many had brand-new Jet Skis or speedboats on driveways.

At the east end of the island, an unmarked speedboat, in which two of the boaters had their faces covered, zoomed past. One looked around nervously, and the other stared at a Post photographer as he took his picture.

“You see these boats race across the river all the time; they run everything,” said James Burns, a special agent with the Drug Enforcement Administration. “Those fellows were probably nervous because they saw you with a camera.”

The island was the home of Mickey “Big Boss Man” Woods, a 38-year-old busted last year and charged with transporting more than 10,000 kilos of Canadian pot through the reservation between 2005 and 2008.

A federal indictment alleges that Woods and his crew of 33, including 16 tribe members from the island and two more from the nearby town of Hogansburg, NY, made tens of millions. The indictment seeks to seize $45 million in alleged proceeds from illegal drugs.

The pot is grown in Canada, Resnick said, and it’s the highest quality and most expensive available in New York City.

“It’s hydroponic, which means it’s grown indoors, and has concentrated levels of THC,” the chemical in pot that creates a high.

“The price is about $3,000 a pound — as opposed to $500 to $1,000 for homegrown. On the street, you’ll pay up to $600 an ounce.”

Coordinated crackdowns have led to several recent arrests, including a state Attorney General’s Office indictment on Oct. 28 of 18 alleged traffickers. They were headed by Scott Jerome, 33, who stands accused of running hundreds of pounds of pot through the reservation with the help of Mohawk tribe members.

One of the biggest arrests came in June, when the DEA broke up what it said was a major ring that pumped hundreds of pounds of pot into New York and other cities on the Eastern seaboard.

There have been several seizures of ecstasy — including one in April and another in September that netted 81,000 pills, which have a street value of $1.6 million, DEA Agent Burns said.

The NYPD got involved after the DEA formed a task force in March “for the specific purpose of targeting criminal organizations that use the reservation for their activities,” he said.

The group, which includes federal border patrol and immigration and customs officers, along with state troopers and local sheriffs and prosecutors, met in late September. They were joined by Resnick and a contingent of other city cops.

“They had a good representation and were very interested in what we had to say about smuggling operations. It’s my understanding that they intend to have some folks up here. It’s been bantered about. They’ve also been talking about that with the State Police.”

Not so, said NYPD spokesman Paul Browne.

“Yes, NYPD narcotics have been briefed regarding activities on the reservation. We cooperate with other agencies by sharing information, but there is now none and never has been any plans to assign any NYPD personnel there.”

If the NYPD does take on a larger role, it could experience resistance from the Mohawks, who have clashed with federal officers.

“They act like they are a sovereign nation, but we can go onto the land any time we want,” said one US Customs and Border Protection guard.

Said another: “When the river freezes, there’s so many snowmobiles out there we don’t even bother. If border patrol tried to police the traffic, there would be a war.”

Tribe leaders have said that drug smugglers represent only a small percentage of their population — and they resent being characterized as a lawless group. None, including a grand chief, would speak on the record.

Leaders are proud of their members. Although the Akwesasne reservation suffers from some of the same problems as others — high unemployment, obesity, alcoholism — it also has successful industries, including tobacco factories, construction and maple syrup.

There is a large presence of Mohawk ironworkers in New York City, many of whom live in The Bronx and Bay Ridge, Brooklyn.

Burns pointed out that although tribe members have been arrested for smuggling, the Mohawks are by no means the only ones involved in illicit trafficking.

“The whole north border is sparsely populated, and there are a lot of places that are unregulated where you can cross,” he said. “There’s a lot going on at the reservation, but that’s not the only place.”